Tough decision, This game is better than the first two in my opinion, although I still play them, but I love my 360 also. Chaos Theory won't play on the 360 either, well at least not on mine. I bought the hard drive seperate and downloaded the update.
You can also play split screen co-op missions.
Not trying to make up your mind for you. Can't tell you if you'll personally enjoy this game, but I can tell you if you like XBox, you'll love 360.
Would like to have you in here to discuss the game.